To perform constant angular velocity (CAV) recording of information on an optical disc, recording parameters need to be optimized for each of the successively changing linear velocities. The term “CAV recording” refers to a technique of recording information onto an optical disc, while changing a recording clock, having a period T, depending on a change in linear velocity, so that the linear density of recorded data is constant.
Japanese Laid-Open Publication No. 2001-344754 discloses a method for determining an optimum recording power level for each of successive linear velocities. In this method, test recording is performed at particular linear velocities in advance. Based on the results, an optimum recording power level is calculated for an arbitrary linear velocity.
Japanese Laid-Open Publication No. 2001-118245 discloses a method for calculating an optimum pulse width for an arbitrary linear velocity, based on the widths of a starting pulse and a final cooling pulse contained in a pulse sequence, which has been previously recorded on an optical disc at a prescribed linear velocity.
However, when the method disclosed in Japanese Laid-Open Publication No. 2001-344754 is used to perform CAV recording of information at high density and high speed (e.g., when information is recorded onto DVD-RAM), an optimum recording power level for an arbitrary linear velocity, which is calculated based on the result of test recordings performed in advance at a particular linear velocity, is different from the actual recording power level for the linear velocity.
When the method disclosed in Japanese Laid-Open Publication No. 2001-118245 is used to perform CAV recording of information at high density and high speed (e.g., when information is recorded onto DVD-RAM), an optimum pulse width for an arbitrary linear velocity, which is calculated based on the widths of a starting pulse and a terminating pulse contained in a pulse sequence which has been previously recorded on an optical disc at a prescribed linear velocity, is different from the optimum pulse width for the arbitrary linear velocity.
These differences are caused by variations in optical discs or variations in the diameter of a light spot produced by recording apparatuses. Therefore, the differences occur even when optical discs are produced by the same manufacturer. The differences are significant when CAV recording of information is performed at a high density and a high speed. Therefore, a technique for generating an optimum pulse sequence corresponding to an arbitrary linear velocity for each combination of an optical disc and a recording apparatus is required.
The present invention is provided to solve the above-described problems. An object of the present invention is to provide a recording method and a recording apparatus for producing an optimum pulse sequence, depending on an arbitrary linear velocity, even when CAV recording of information is performed at a high density and a high speed, and a recording medium.